ดาวน์โหลด WinTUI 2.8.0

- Color Theme picker. Eight curated palettes — Sweet Pink (default), WinTUI Midnight, Catppuccin (Mocha + Latte), Nord, Dracula, Tokyo Night, Ember (Dusk + Dawn), Monochrome. Cycle in Settings (Left/Right/Space). Every theme ships matching Dark and Light variants; the variant is picked automatically from the terminal's detected background color via tea.RequestBackgroundColor, so themes read correctly on both dark and light terminals without configuration.
- Theme Background setting (opt-in). When set to "theme", the active palette tints the terminal background via OSC 11. Default "terminal" leaves the terminal background untouched. Off by default because OSC 11 support varies across terminals; on unsupported terminals this setting is a no-op.
- Theme engine. A single setActiveTheme call rebinds every package-level color and rebuilds every cached lipgloss.Style. Model-held styles (spinners, text inputs, viewport border, progress bar, all six help slots) ride a themeAware interface — every screen returns an updated value via applyTheme() screen and cascades into its sub-components. A conformance test asserts every screen reachable via createScreen implements the interface. Animated header gradient now generated via lipgloss.Blend1D from two endpoint colors per theme.
- Visible polish. All six help bar slots styled (FullKey/FullDesc/FullSeparator were previously left at bubbles defaults). Help separator sources from the palette dim slot instead of hardcoded ANSI 238. Window title set to "WinTUI" via the v2 tea.View.WindowTitle field.
- No breaking changes, no new Win32 surface. settings.json gains two optional keys (theme, theme_background); both default-safe. cache.json is untouched.